1. Field of the Invention
This invention relates to a process for producing an antithrombogenic vinyl acetate polymer or hydrolyzate.
2. Description of the Prior Art
A material obtained by fixing urokinase to the surface of a nylon tube is described in A. Sugitachi, K. Takagi, The International Journal of Artificial Organs, Vol. 1, No. 2, pp. 88-92 (1978) as having superior antithrombogenic properties and as being suitable for clinical applications such as in the form of surgical drains, intravenous catheters, etc. Sugitachi et al, supra, state that the nylon tube is somewhat non-elastic for clinical applications and to remedy this defect urokinase was fixed to a silicone tube which is softer but does not have as good antithrombogenic property.
The inventors of the present application have previously developed a process for preparing an elastic antithrombogenic material by fixing a fibrinolytic substance to a polyester elastomer, e.g., as disclosed in Japanese patent application (OPI) No. 113194/78 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"). However, the resulting elastic antithrombogenic material is opaque, has a lower creep resistance than silicone, and is unable to accommodate a large volume of contrast media for X-ray photography such as barium sulfate which is detrimental to its softness.
Two U.S. patent applications are now pending filed in the names of the present inventors. One is entitled "A Process for Producing an Antithrombogenic Material by Fixation of a Synthesized Fibrinolytic Compound", Ser. No. 844,856, filed Oct. 25, 1977, U.S. Pat. No. 4,273,873 and the other is "A Process for Producing an Antithrombogenic Polyurethane by Fixation of a Fibrinolytic Enzyme to the Surface of Polyurethane", Ser. No. 928,496, filed July 27, 1978, now abandoned.